Subcritical water oxidation of 6-aminopenicillanic acid and cloxacillin using H₂O₂, K₂S₂O₈, and O₂

ABSTRACT

This study was undertaken to investigate the degradation of 6-aminopenicillanic acid (6-APA) and cloxacillin in aqueous solution by the combined effect of subcritical water and the oxidising agents O₂, H₂O₂, and K₂S₂O₈. Nano ZnO was used as a solid catalyst. Response surface methodology was used to determine the optimum experimental parameters (temperature, treatment time, and concentration of oxidising agent). For 6-APA, the maximum organic carbon (TOC) removal rates of 83.54%, 81.11% and 42.42% were obtained using H₂O₂, K₂S₂O₈, and O₂, respectively. For cloxacillin, the maximum TOC removal rates of 67.69%, 76.02% and 14.45% were obtained using H₂O₂, K₂S₂O₈, and O₂, respectively. Additionally, the impact of nano and commercial ZnO on TOC removal rates was determined. Secondary ions produced during the degradation process—such as nitrite, nitrate, sulphate and chloride—were determined using ion chromatography.

KEYWORDS:

• ANOVA
• degradation
• nano ZnO
• response surface methodology
• total organic carbon removal

Acknowledgments

The authors thank the researchers of MEITAM and Associate Professor Dr Belgin Gözmen for their opinion and assistance. They also thank Dr Dimitrios Kalderis for regulation of English grammar.

Funding

Mersin University Research Fund supported this research (Project No.: BAP-FBE KB (EY) 2014-1 DR).